In an axial flow rotary machine, the rotor assemblies are commonly provided with rotor blades extending outwardly therefrom. The rotor blades have a root having a groove which is adapted to engage a corresponding groove in the disk for retention of the rotor blade. An airfoil extends outwardly from the root and is used as a flow directing device for working medium gases. The airfoil has a convex side and a concave side. Each rotor blade may also be provided with a shroud, such as a tip shroud at the outer end of the airfoil. The shroud extends circumferentially to engage the shrouds of adjacent rotor blades. During operation of the rotary machine, the rotor blades and shrouds are subjected to fluctuating gas loads and to high temperatures. These fluctuating gas loads induce vibrations in the blades which are damped by rubbing between the shrouds. Such rubbing causes wear. After the rotor blade has been used for some time it becomes necessary to restore any shroud which has worn surfaces or to discard the blade. It is necessary to inspect the shroud to determine if the shroud has suffered wear or no longer has a sufficient amount of pretwist to exert the necessary preload required for operation. One method of examining the faces is to measure cross face dimensions. However, it is difficult to insure that measurements are being made with the blade in the correct orientation to determine if the blade has sufficient pretwist or if the surfaces are unworn.